In order to accommodate very high data rates in wireless local area networks, enhancements to existing standards, e.g., to the IEEE 802.11 wireless standard (also known commercially as WiFi™) are being developed. The enhancements are IEEE 802.11ac and 802.11ad. In addition, another specification, known as WiGig (for Wireless Gigabit) managed by the WiGig Alliance (WGA), is being developed for 60 Gigahertz (GHz) operation.
The WGA and 802.11ad proposals use a scheduled media access control (MAC) protocol whereby access to the frequency band is allocated in a scheduled manner. Nevertheless, overlapped scheduling can occur due to multiple Basic Service Sets within radio range of each other. Even if the Basic Service Sets offset their beacon transmissions and only take a fraction of the available medium time, clock offsets in the wireless devices still can cause regular transmissions, such as beacons, to drift and consequently overlap with each other. Overlapped scheduling can also occur if one scheduler allocates 95% of the medium time to its clients, and another overlapped scheduler does the same.